This invention relates to the field of refuse processing and finds particular application in vacuum transport systems which handle refuse, such as household garbage.
Conventionally, the refuse transported by and separated from the air stream in the system, is periodically discharged therefrom through a discharge pipe and deposited, for example, in containers for final disposition or further conveyance. Conventionally the discharge process is discontinuous and sluice-means are used to avoid open communication between the closed vacuum transport system and the ambient atmosphere. However, it is desirable to perform the refuse discharge operation in a continuous manner while insuring that such refuse discharge operation does not adversely affect the efficiency of the vacuum transport system by allowing air to be drawn in through the open passage, and, accordingly, it is a desideratum to block this passage against substantial inflow of air even while the discharge operation is in progress to thus maintain the transport system substantially vacuum tight.
It has now been recognized that a feasible manner of maintaining the system vacuum tight while the refuse discharge operation is in progress is to provide a blockage by the refuse itself which thus is to function essentially as a vacuum plug as it is extruded through the discharge opening.
It has been found, however, that in devices used heretofore, the density of the refuse in the extrusion phase, has not been sufficient to function satisfactorily as a vacuum plug. The known discharge devices include a reciprocating pusher, which, in its withdrawn position allows refuse material to be introduced into the discharge tube inlet through a hopper connected to the vacuum transport system. Thereafter, the pusher is actuated and thus the refuse material is driven into the discharge tube. Subsequently, the pusher is withdrawn to receive additional refuse material. This stepped feed causes an intermittent discharge of the refuse at the downstream (discharge) and of the discharge pipe.